Compact fluid compressor

ABSTRACT

A regenerative compressor in accordance with the invention described herein comprises a stator and a rotor coaxial therewith to form a motor. Concentric to the motor and between its ends is a compressor chamber having inlet and exhaust openings. A compressor wheel is mounted on the rotor and projects into the compressor chamber for providing a high compression output in a limited space.

United States Patent I H113,601,507

[72] lnventor Dwight EJ-larr's {56] ReferencesCited 2 1 I N ggfig UNITEDSTATES PATENTS a 2,768,583 10/1956 Richardetal. 3l0/67X fig g 'g'gg?2,772,046 11/1956 Sh0mphe..... 310/67X 1 2,926,838 3 1960 VanRijn3lO/67X [73] Assignee Rotron Incorporated Woodstock, N.Y. PrimaryExaminer- Robert M. Walker Attorney-Brumbaugh, Graves, Donohue & Raymond[54] COMPACT FLUID COMPRESSOR 7 clmmsz Drawmg ABSTRACT: A regenerativecompressor in accordance with' [52] US. Cl 417/354, the inventiondescribed herein comprises a stator and a rotor 310/67 coaxial therewithto form a motor. Concentric to the motor [5 1] Int. Cl ..F04b 17/00, andbetween its ends is a compressor chamber having inlet and H02k 7/00exhaust openings. A compressor wheel is mounted on the [50] Field ofSearch n 417/354, rotor and projects into the compressor chamber forproviding 423; 310/67 21 high compression output ina limited space.

1 l -45 ;I1l I fa I l I f i /& 6Z-. 44 6 0 5 6 1 7'37 2 22 l 772PATENTED AUG24 197:

INVENTOR. DWIGHT E. HARP/8 M%M M his ATTORNEYS.

V COMPACT FLUID COMPRESSOR '5 In many applications involving the use ofelectric motors or electronic components, it is necessary to remove theheat generated in order to maintain the operating life or charac--teristics of the unit. To accomplish this, it is usual to provide anelectric fan that will remove the heat generated and provide the vabove-described advantages. Generally, however, space is at a premiumand the size of the fan must be kept to a minimum in order to becompatible with the installation.

Another application requiring compact exhaust fans is the removal of wetor corrosive vapors, such as given ofi by the chemical solutionsemployed in certain types of duplicating or printing machines. Inaddition to the space problem, it is a necessity in the design of fansfor this type of application, that the motor and blower structure beprotected from the harmful efl'ects of the vapors.

In all of the above-described applications still another factor must beconsidered, i.e., the fan must provide a high compression in order toremove as much of the heat and vapors as possible. Compact tube axialfans and centrifugal compressors are available, but these units do notprovide a high enough output for many requirements nor are such unitsresistant to the harmful effects of excessive moisture orcorrosivevapors.

Where high outputs are required, designers have frequently employedregenerative compressors. However, presently available regenerativecompressors are too large for many environments, conventionally,consisting of a shaft extending axially from an electric motor andcarrying an impeller that projectsinto a compressor chamber spaced fromthe motor. The overall dimensions, particularly in the axial direction,are thus often too large to be satisfactorily utilized in theenvironments described above. These devices also present somestructuraldifficulties that add to their complexity and cost.

It is an object of this invention, therefore, to provide a fan capableof a high compression and having a relatively small axial length so asto be usable where space is at a premium and a high output is required.

It is another object of this invention to provide a fan that is capableof exhausting corrosive or wet vapors while preventing detrimentaleffect to the motor.

It is still another object of this invention to provide a regenerativecompressor of the type described above wherein the problems associatedwith mounting the impeller to the shaft are alleviated and wherein theheat of the motor is dissipated in the airstream driven by the impeller.

Briefly described, this invention comprises a cup-shaped rotor assemblymounted for rotation about a stator assembly and wherein the impellerwheel is mounted directly to the rotor assembly and projects radiallytherefrom at a point located between the ends of the motor. An annularcompressor chamber is also located between the ends of the motor and iscoaxial therewith, so as to receive the impeller wheel. By thisarrangement, the size of the fan is significantly reduced and motor heatis dissipated into the airstream exhausted by the compressor.

If the motor is to be used to exhaust corrosive or wet vapors, the motorassembly may be encapsulated in a suitable plastic that prevents thedetrimental effect of these vapors on the motor.

For a better understanding of the present invention, reference is madeto the following specification and the accompanying drawings, in which:I

. FIG. 1 is an elevation view of a regenerative compressor in accordancewith the invention; and

FIG. 2 is a cross-sectional view of the compressor shown in FIG. 1,taken along the line 2 -2.

Referring to the drawings, there is disclosed (FIG. 2) acentrallydisposed stator assembly surrounded by a cup-shaped rotor assembly 12 toform a motor carried in a housing 56, 58. Located coaxially with themotor is an annular substantially closed compressor chamber 16 ofgenerally toroidal configuration that receives a suitable impellerassembly 18 secured directly to the rotor assembly 12.

, connected to an alternating current source in any conventional fashionto provide the revolving magnetic field. A flanged member 26 includes acollar portion 28 received in the aperture of the stator assembly 10 anda flange 30 projecting radially from the collar portion adjacent one endof the stator assembly. At the outer edge of the flange 30, a pluralityof slots 32 are formed for a purpose to be fully explained hereinafter.

Molded about the stator assembly 10 is a plastic material 24 that may,if the fan is to be utilized to exhaust wet or corrosive vapors,completely encapsulate the statorand provide a protective coating forthe core 20. Otherwise, the plastic 24 need not encapsulate the outsidediameter of the core 20. During the molding operation, plastic will flowthrough the openings 32 to establish an interlock for the member 26.Along the faces of the flange 30 the plastic stops a distance from theend to leave a projecting rim 34 around the circumference of the statorassembly. The purpose of this rim will be fully explained hereinafter.

The rotor assembly 12 is a generally cup-shaped arrangement including aflat base portion 36 supporting the annular laminations 38 and an endring 40. Laminations 38 project axially from the outer periphery of thebase portion 36 so as to cooperate with the core 20 and provide anelectric motor. Also projecting axially from the'inner face of the baseportion 36 is a central boss member 42, the purpose of which will beexplained hereinafter.

As mentioned previously, the impeller assembly 18 is carried on therotor assembly 12 and comprises an annular mounting ring 44 that isfixedly secured to the outerperiphery of the rotor assembly at a pointintermediate the ends' thereof. As shown in FIG. 2, the ring 44 definesa fractional part of the innermost surface of the compressor chamber 16.Thus the ring 44 completes the chamber 16 defined by the housing. Aplurality of regenerative compressor blades 46, which may be curved orplanar, project radially from the outer surface of the ring member 44and extend into the compressor chamber'1 6. The blades 46 serve tocompress gases which enter the chamber 16 as they are forced to move ina generally circulatory mannerthrough a substantial portion of thechamber 16. The blades 46extend to the outermost surface that definesthe chamber 16 as shown in FIG. 2. It should be apparent that thisarrangement reduces the axial length of the compressor to that of theelectric motor and also eliminates the problems of attaching theimpeller to a narrow cylindrical shaft. Motor heat is readily dissipatedsince the fan blades 46 and ring member 44 are made of a metal orplastic'having good thermal conductivity, and thus provide a good heatconducting path from the motor to the chamber 16 where the heat isexhausted with the air.

Preferably, the impeller assembly 18 should be secured to therotor'assembly 12 in a very rigid manner due to the high forces actingthereon. The accomplishment of such a joint is difficult when the fan isto be extremely small because of the lightweight materials beingutilized However, the joint described herein provides the desiredrigidity while allowing use of the materials desired. The end of therotor base 36 is cut to form a step 37 extending around its periphery sothat two surfaces are provided. Depending inwardly from the ring 44 is alip portion 45 that is adapted to butt against thetwo surfaces providedby the step 37. Since the ring 44 extends along the laminations 38,three distinct areas of contact'between the ring and rotor assembly areprovided and a rigid joint is achieved. The left-hand portion of thering may be'extended, as at 47, under the chamber 16 to provide agreater contact area between the ring and the rotor assembly and animproved fluid seal.

When assembled in their operative relationship, the boss member 42projects into the central aperture of the stator assembly 10. Rotatablysupporting the rotor assembly 12 is a shaft 48 fixedly carried by theboss member 32 and extending through the remaining portion of thecentral aperture. A'suitaretaining washer 54 is snapped over the end ofthe shaft 48- also in a manner that is well known in the art.

A preferred form of housing includes a first housing portion 56 adaptedto be secured to the stator assembly and has a cup shaped portion 58that may be integrally molded with a semicircular wall portion 60forming a portion of the toroidal chamber 16. The end face of thecup-shaped portion 58 includes an annular opening therethrough having anundercut lip portion 62 projecting inwardly around the periphery of theopening. When assembled, the rim 34 on the stator assembly will bereceived in the lip 62 and adhesively secured thereto. A removable endcap 64 may be placed in the open end of the central opening through thestator assembly to seal the motor.

Also included as part of the housing is a back wall portion 66 that isgenerally cup-shaped and complementary to the chamber wall 60. Whenassembled, e.g., by suitable clips 68, the housing and the compressorchamber 16 are formed. The housing thus defines at least three sides ofan annular compression chamber. As shown by FIG. 1, this chamber is ofsubstantially constant cross-sectional area.

The compressor chamber includes an inlet 70 and an outlet 72, betweenwhich is located a stripper (not shown) projecting inwardly from thechamber wall 60 at a point between the inlet and exhaust opening so asto guide the air through the exhaust opening. Any convenient shape ofinlet and outlet may be employed, to suit the particular application andenvironment. In the illustrated embodiment, the inlet includes agenerally tubular coupling element for connection to a conduit, and theoutlet comprises simply an opening in the wall 60 of the compressorchamber. Mounting lugs 74 may also be provided to secure the fan to asupport member.

It should be apparent from the preceding description that a narrow fancapable of a high delivery is provided wherein the heat dissipation andimpeller mounting problems are solved.

tive embodiment of this invention, various modifications will occur tothose skilled in the art to which this invention pertains. Accordingly,it is not desired to limit the invention to the exact featuresdisclosed, but to encompass all such modifications.

I claim:

1. A regenerative compressor comprising a centrally disposed statorassembly, a rotor assembly surrounding said stator assembly andoperatively associated therewith to form an electric motor, a housingsecured to said stator, said housing partially defining an annular andsubstantially closed compression chamber surrounding said rotor assemblyand disposed substantially between the ends thereof, said chamberAdditionally, it should be noted that if the stator windings 20 arecompletely encapsulated in plastic, the fan may be used to exhaust wetor corrosive vapor.

While in the foregoing there has been disclosed an illustra- 3. Aregenerative compressor according to claim 1 wherein said housingdefines at least three sides of said chamber.

4. A regenerative compressor according to claim 1 wherein said ringdefines a fractional part of the innermost surface of said chamber andthe remainder of said chamber is defined by said housing.

5. A regenerative compressor according to claim 4 wherein said chamberis generally toroidal in shape.

6.'A regenerative compressor according to claim 1 wherein said chamberis of substantially constant cross-sectional area and said regenerativecompressor blades extend to the outermost surface that defines saidchamber.

7. A regenerative compressor according to claim 1 wherein said rotorassembly includes a cup-shaped member surround ing the stator assembly,a portion of which forms a step around its periphery, and said ringincludes a lip which butts against two surfaces of said step to providea rigid joint between said ring and said rotor assembly.

1. A regenerative compressor comprising a cEntrally disposed statorassembly, a rotor assembly surrounding said stator assembly andoperatively associated therewith to form an electric motor, a housingsecured to said stator, said housing partially defining an annular andsubstantially closed compression chamber surrounding said rotor assemblyand disposed substantially between the ends thereof, said chamber beingconcentric with said stator assembly and said rotor assembly, a ringrigidly secured to said rotor defining at least a part of the innermostsurface of said chamber, a plurality of regenerative compressor bladesdepending from said ring and extending into said chamber whereby gaseswhich enter said chamber are compressed as they are forced to movethrough a substantial portion thereof in a circulatory manner.
 2. Aregenerative compressor according to claim 1 wherein said ring isfixedly secured to said rotor assembly at a point intermediate the endsthereof.
 3. A regenerative compressor according to claim 1 wherein saidhousing defines at least three sides of said chamber.
 4. A regenerativecompressor according to claim 1 wherein said ring defines a fractionalpart of the innermost surface of said chamber and the remainder of saidchamber is defined by said housing.
 5. A regenerative compressoraccording to claim 4 wherein said chamber is generally toroidal inshape.
 6. A regenerative compressor according to claim 1 wherein saidchamber is of substantially constant cross-sectional area and saidregenerative compressor blades extend to the outermost surface thatdefines said chamber.
 7. A regenerative compressor according to claim 1wherein said rotor assembly includes a cup-shaped member surrounding thestator assembly, a portion of which forms a step around its periphery,and said ring includes a lip which butts against two surfaces of saidstep to provide a rigid joint between said ring and said rotor assembly.